Turn off the device.
Once the phone is off, hold the volume up, home, and power buttons down simultaneously.
Continue to hold this combination while the phone boots, until the screen shows the Android Robot.After a few moments, you will have access to the phone’s boot menu.
Using the volume up/down buttons to navigate, and the power button to make selections, find and select the Wipe Data/Factory Reset option.Scroll down to Yes, delete all user data, and press the power button once again. You will notice script scrolling along the bottom of the screen, which will end in Data Wipe Complete.Once the operation is complete, press the power button once more to reset the device.The phone has now been returned to factory settings, and you no longer have to worry about that lost password. Just make sure that you remember your new one.